This invention generally relates to a catheter system which is suitable for intravascular procedures such as percutaneous transluminal coronary angioplasty (PTCA) and which allows for the exchange of guidewires and catheters during such procedures.
In classic PICA procedures, a guiding catheter having a preshaped distal tip is percutaneously introduced into the cardiovascular system of a patient and advanced therein until the preshaped distal tip thereof is disposed within the aorta adjacent the ostium of the desired coronary artery. The guiding catheter is twisted or torqued from the proximal end to turn the distal tip of the guiding catheter so that it can be guided into the coronary ostium. A dilatation catheter having a balloon on the distal end thereof and a guidewire slidably disposed within an inner lumen of the dilatation catheter are introduced into and advanced through the guiding catheter to the distal tip thereof. The distal tip of the guidewire is usually manually shaped (i.e. curved) by the physician or one of the attendants before the guidewire is introduced into the guiding catheter along with the dilatation catheter. The guidewire is first advanced out the distal tip of the guiding catheter, which is seated in the ostium of the patient""s coronary artery, into the patient""s coronary artery. A torque is applied to the proximal end of the guidewire, which extends out of the patient, to guide the curved or otherwise shaped distal end of the guidewire as the guidewire is advanced within the coronary anatomy until the shaped distal end of the guidewire enters the desired artery. The advancement of the guidewire within the selected artery continues until it crosses the lesion to be dilated. The dilatation catheter is then advanced out of the distal tip of the guiding catheter, over the previously advanced guidewire, until the balloon on the distal extremity of the dilatation catheter is properly positioned across the lesion. Once properly positioned, the flexible, relatively inelastic balloon is inflated to a predetermined size with radiopaque liquid at relatively high pressures (e.g., 4-12 atmospheres) to dilate the stenosed region of the diseased artery. The balloon is then deflated so that the dilatation catheter can be removed from the dilated stenosis and blood flow can then be resumed therethrough.
Further details of guiding catheters, dilatation catheters, guidewires, and the like for angioplasty procedures can be found in U.S. Pat. No. 4,323,071 (Simpson-Robert); U.S. Pat. No. 4,439,185 (Lundquist); U.S. Pat. No. 4,468,224 (Enzmann et al.); U.S. Pat. No. 4,516,972 (Samson); U.S. Pat. No. 4,438,622 (Samson et al.); U.S. Pat. No. 4,554,929 (Samson et al.); U.S. Pat. No. 4,582,185 (Samson); U.S. Pat. No. 4,616,652 (Simpson); U.S. Pat. No. 4,638,805 (Powell); U.S. Pat. No. 4,748,986 (Morrison et al.); U.S. Pat. No. 4,898,577 (Badger et al.); and U.S. Pat. No. 4,748,982 (Horzewski et al.) which are hereby incorporated herein in their entirety by reference thereto.
Recently, the licensee of the present invention, Advanced Cardiovascular Systems, Inc., introduced into the market place an improved dilatation catheter which is described and claimed in copending application Ser. No. 07/550,801 (Yock), filed Jul. 9, 1990 and U.S. Pat. No. 4,748,982 (Horzewski et al.). This dilatation catheter has a short guidewire-receiving sleeve or inner lumen extending through just the distal portion of the catheter. The sleeve extends proximally at least 10 cm, typically about 25 cm, from a guidewire port in the distal end of the catheter to another guidewire port in the wall of the catheter. A slit is provided in the catheter wall which extends distally from the second guidewire port to a location proximal to the proximal end of the inflatable balloon. The structure of the catheter allows for the rapid exchange of the catheter without the need for an exchange wire or adding a guidewire extension to the proximal end of the guidewire.
The catheter design embodying the Yock and Horzewski et al. improvements has been widely praised by members of the medical profession and has met with much commercial success in the market place. Nonetheless, there are some inconveniences in its use because the catheter does not allow for the exchange or replacement of the guidewire. For example, the shaped distal tip of the guidewire may become deformed in use or the shape of the distal tip or the size of the guidewire may be found to be no longer suitable for the particular procedure within the patient""s vasculature. In this instance the physician might want to remove the guidewire and reshape the distal tip or replace the first guidewire with another having the desired size, stiffness or shape. However, when the guidewire in a dilatation catheter system embodying the Yock and Horzewski et al. improvements is removed, access to the desired arterial location through the distal guidewire lumen of the catheter is lost. Unfortunately, there is no way to clinically determine before the guidewire is inserted into the patient in an angioplasty procedure whether a guidewire or a catheter will have to be exchanged during the procedure.
What has been needed and heretofore unavailable is an intravascular catheter system which allows for the rapid exchange of either the catheter or the guidewire during an intravascular procedure without losing access to the desired region of the patient""s arterial system. The present invention satisfies this and other needs.
This invention is directed to a catheter system which can be used in an over-the-wire type mode and which can also allow for the exchange of either a guidewire or a catheter mounted over a guidewire during an intraluminal procedure such as PTCA without losing access to the body lumen and the method of using such a catheter system.
The catheter system of the invention generally comprises an elongated catheter body with proximal and distal ends, a diagnostic or therapeutic means, such as an inflatable balloon positioned on a distal portion of the body and a guidewire-receiving inner lumen extending within the body to the distal end thereof. The catheter body has a first guidewire port at or near the proximal end thereof, a second guidewire port in the catheter body between the first port and the diagnostic or therapeutic means, and a third guidewire port in the distal end of the catheter, all of which are in communication with the guidewire-receiving inner lumen within the catheter body. The first port is generally at or close to the proximal end of the catheter body, e.g. not more than about 30 cm therefrom, and, preferably, is not more than about 10 cm from the proximal end of the catheter body. The second port is spaced closer to the diagnostic or therapeutic means than it is to the first port and generally is at least about 10 cm from the distal end of the catheter body preferably about 15 cm to about 40 cm.
In a presently preferred embodiment the catheter is a balloon dilatation catheter adapted to perform PTCA procedures. The catheter has a catheter body with two inner lumen extending essentially the length thereof, one of the lumens being a guidewire-receiving lumen and the other lumen being adapted to direct inflation fluid to the interior of a dilatation balloon on the distal portion of the catheter. One of the attractive features of this catheter design is that the catheter can be used as an over-the-wire type dilatation catheter in a conventional fashion, yet it allows both the catheter and the guidewire to be exchanged during the PTCA procedure. Similar catheter designs can be used with other intraluminal catheters which have diagnostic or therapeutic means on the distal portion of the catheter.
To facilitate the separation of the guidewire and the catheter during an exchange thereof, a slit is preferably provided in the wall of the catheter body which defines at least part of the guidewire-receiving inner lumen. The slit extends distally from the first guidewire port, preferably to the second port. A second slit should extend distally from the second guidewire port to a location proximately adjacent the diagnostic or therapeutic means.
To replace a catheter during an intraluminal procedure such as PTCA, the in-place catheter is pulled proximally over the guidewire from the proximal end of the catheter. If the in-place guidewire extends out the second guidewire port, the catheter is withdrawn peeling the catheter off of the guidewire through the slit extending distally from the second guidewire until the distal end of the catheter exits the proximal end of the guiding catheter or an adapter attached thereto at which point the guidewire can be manually held in position while the catheter is removed from the proximal end thereof. If the in-place guidewire exits the inner lumen of the catheter from the first guidewire port, the catheter is separated from the guidewire by peeling the catheter away from the guidewire through the slit which extends between the first and second guidewire port as the catheter is withdrawn from the proximal end of the guiding catheter or the adapter attached thereto until the guidewire exits the second guidewire port. The separation of the catheter from the guidewire continues as previously described with the catheter being peeled off of the guidewire through the slit which extends distally from the second guidewire port. The catheter is further withdrawn until the distal end of the catheter exits the proximal end of the guiding catheter and which time the guidewire can be manually held while the catheter is pulled off the proximal end of the guidewire.
Once the catheter has been removed from the proximal end of the in-place guidewire, the proximal end of the in-place guidewire is inserted into the third guidewire port in the distal end of a replacement catheter and then the replacement catheter can be advanced into the patient""s vasculature over the in-place guidewire to perform the intravascular procedure. The proximal end of the guidewire can be directed out of either the second or the first guidewire port in the catheter body depending upon the needs of the physician.
The catheter system of the invention also allows for the exchange of an in-place guidewire during an intraluminal procedure while holding the catheter in place so as to maintain access to the intraluminal position. To replace an in-place guidewire, it is removed from the guidewire-receiving inner lumen of the catheter and the patient by pulling on its proximal end which extends out of the patient. When the in-place guidewire is removed from the inner lumen of the in-place catheter, the replacement guidewire is inserted into the guidewire-receiving inner lumen of the in-place catheter through the proximal guidewire port and advanced through the guidewire-receiving inner lumen and out the third port in the distal end thereof to the desired location within the patient""s body lumen. If the in-place guidewire extends out the second guidewire port, it may be desirable to have the replacement guidewire inserted into the proximal portion of the guidewire-receiving inner lumen through the first or proximal guidewire port before the in-place guidewire is removed from the distal portion of the inner lumen so that there is little chance of losing access to the lumenal location by the accidental movement of the in-place catheter. When the replacement guidewire is advanced through the in-place catheter and properly positioned in a desired location therein, e.g. across a stenosis in a patient""s artery which is to be dilated, the catheter may then be advanced over the replacement guidewire to the desired location so as to perform the desired diagnostic or therapeutic treatment therein.
The intravascular catheter of the invention also allows for the removal and reinsertion of a guidewire, for example, when the physician wishes to change the shape of the distal end of a guidewire during a procedure. In this operative modality, the in-place guidewire can be withdrawn in essentially the manner described above, the distal tip thereof reshaped and then be reintroduced into the in-place catheter in essentially the same manner as described above.
As will become more apparent from the following detailed description of the invention, the intravascular catheter system of the invention allows for a wide variety of intravascular procedures which were heretofore impossible to perform with a single catheter system. These and other advantages are described in the following detailed description when taken in conjunction with the accompanying exemplary drawings.